As a conventional vehicle of this type, a bus is proposed in which a plurality of gas fuel tanks each having a valve body mounted to a port opening at a front end in a longitudinal direction and store compression natural gas are mounted on a roof of a vehicle so that the longitudinal direction of the gas fuel tanks is in a vehicle fore/aft direction (for example, see Patent Document 1). In this vehicle, the longitudinal direction of the gas fuel tank is in the vehicle fore/aft direction, and thus a gas fuel tank longer than a vehicle width can be used.    [Patent Document 1] Japanese Patent Laid-Open No. 2001-239845